Skip to main content

Chapter 7 - Landforms & Their Evolution

"Geomorphology" - Study of the earth surface

A landform is a feature on the Earth's surface that is part of the terrain. Mountains, hills, plateaus, and plains are the four major types of landforms. Minor landforms include buttes, canyons, valleys, and basins.



Landforms by Rivers

 Erosion
The Erosion results first into Rills then - Gullies then - Valleys

  • Rills - are narrow and shallow channels which are eroded into unprotected soil by hillslope runoff. 
  • Gully - is a landform created by running water, eroding sharply into soil, typically on a hillside. Gullies resemble large ditches or small valleys
  • Valley - is a low area between hills, often with a river running through it. Types - 

V-Shape Valley - formed in Mountain region
U-Shape Valley - carved by glaciers


  • Canyon or Gorge - is a deep ravine between pairs of escarpments or cliffs
  • Potholes - are cylindrical holes drilled into the bed of a river that vary in depth & diameter from a few centimetres to several metres. They’re found in the upper course of a river
  • Meanders - are bends in a river that form as a river’s sinuosity increases. The sinuosity of a river is a measurement of how much a river varies from a straight line.
  • Oxbow Lakes - Oxbow lakes are an evolution of meanders that undergo extensive deposition and erosion. Strong erosion takes place on the outside bend of a meander while deposition takes place on the inside bend. As a result, the neck of a meander narrows. Deposition eventually separates the cutoff from the main channel leaving behind an oxbow lake.


Deposition

  • Alluvial fan - is a fan- or cone-shaped deposit of sediment crossed and built up by streams. Mostly formed in Arid & Semi Arid climates
  • Floodplains - Floodplains are large, flat expanses of land that form on either side of a river. The floodplain is the area that a river floods onto when it’s experiencing high discharge. 
  • Natural Levees - are natural embankments produced, ironically, when a river floods. When a river floods, it deposits its load over the flood plain due to a dramatic drop in the river’s velocity as friction increases greatly.
  • Deltas - are depositional landforms found at the mouth of a river where the river meets a body of water with a lower velocity than the river

Term "Delta" is coined by Herodotus (father of Geography)

Landforms by Glaciers

  • Cirque - are Armchair shaped hollow floor formed by sliding snow
  • Tarn - are lakes formed by melted glacier of Cirque
  • Fiord - are narrow inlet with steep sides created by glacial erosion
  • U-Shape Valley - formed by glacial erosion
  • Hanging Valley - formed with the help of tributary
  • Moraine - are materials transported & deposited by glacier
  • Eskers - are Zig Zag hills with sand & gravels
  • Drumlines - are Oval shaped hills


Landforms by Wind

  • Mushroom rock - also called rock pedestal or a pedestal rock, is a naturally occurring rock whose shape resembles a mushroom. Usually found in desert areas, these rocks form over thousands of years when wind erosion 
  • Sand Dunes - is a hill of sand built by wind by accumulation of sand grains shaped into a mound or ridge by the wind under the influence of gravity.
  • Barchan - are crescent-shaped sand dunes
  • Loess - are finer soils in silt form found in desert
Labels:

Comments

Post a Comment

Popular posts from this blog

Easy way to understand Direct and Indirect speech rules

Introduction. There two ways to convey a message of a person, or the words spoken by a person to other person. 1.       Direct speech 2.       Indirect speech Suppose your friend whose name is Vipul tells you in College , “I will give you a pen”. You come to home and you want to tell your brother what your friend told you. There are two ways to tell him. Direct speech:   Vipul said, “I will give you a pen”. Indirect Speech:  Vipul said that he would give me a pen. In direct speech   the original words of person are narrated (no change is made) and are enclosed in quotation mark. While in indirect speech some changes are made in original words of the person because these words have been spoken in past so the tense will change accordingly and pronoun may also be changed accordingly. In indirect speech  the statement of the person is not enclosed in quotation marks, the word “ that ” may be used before the statement to show that it is indirect sp
3 comments
Read more

English Error Spotting - Previous Year Questions of SSC CGL

Competition Zenith brings you a post on Error Spotting to boost your English for competitive exams. We are providing you the specifically chosen questions from previous year papers of SSC CGL with the best possible explanation in simplest of the language. Below are some questions with explanation: Questions 1. Have trust on(a)/God and everything(b) /will be right.(c) /(d) No error 2. The cattles (a) /are grazing (b) /in the fields.(c) /(d) No error 3. He is one of (a)/ the best novelists (b) /that has ever lived. Do you agree? (c)/no error (d) 4. On a rainy day (a) /I enjoy to watch TV (b) / with a hot cup of tea.(c ) /no error(d) 5. No sooner did (a)/I reach (b)/ Patna railway station than the train departed(c)/no error (d) 6. There is no agreement (a) / between you and I (b) /so we are free to go our way(c) /no error (d) 7. A variety of books (a) / is available in the market (b) / to help the students qualify the competitive examinations.(c) /no error 8.
4 comments
Read more

Spotting Error Quiz IV - With Explanation For SSC Exam 2015

  Hello Readers, As you know that Spotting Error types question is an important part of competitive examinations and seldom any book provide you the detailed solution. So we have decided to provide you the previous year questions of  spotting error along with the Explanation . If you like it let us know, you can also ask for detailed solutions of questions that are bothering you. 1.     I found (a)/ the two first chapters of the book (b)/ particularly interesting. (c)/ No error (d) Answer    (b) Explanation : It should be   ‘the first two chapters’ . 2.     Bacon, the father of the English easy (a) / had a thirst (b) / of knowledge (c) / No error (d) Answer    (a) Explanation : The English means the citizen of England.   Article is not used before language
4 comments
Read more